{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://stac-extensions.github.io/processing/v1.2.0/schema.json#",
  "title": "Processing Extension",
  "description": "STAC Processing Extension for STAC Items and STAC Collections.",
  "type": "object",
  "required": [
    "stac_extensions"
  ],
  "properties": {
    "stac_extensions": {
      "type": "array",
      "contains": {
        "const": "https://stac-extensions.github.io/processing/v1.2.0/schema.json"
      }
    }
  },
  "anyOf": [
    {
      "$comment": "This is the schema for STAC Items.",
      "type": "object",
      "required": [
        "type",
        "properties",
        "assets"
      ],
      "properties": {
        "type": {
          "const": "Feature"
        },
        "properties": {
          "allOf": [
            {
              "$ref": "#/definitions/require_any_field"
            },
            {
              "$ref": "#/definitions/fields"
            }
          ]
        },
        "assets": {
          "$comment": "This validates the fields in Item Assets, but does not require them.",
          "type": "object",
          "additionalProperties": {
            "$ref": "#/definitions/fields"
          }
        }
      }
    },
    {
      "$comment": "This is the schema for STAC Collections.",
      "type": "object",
      "required": [
        "type"
      ],
      "properties": {
        "type": {
          "const": "Collection"
        },
        "providers": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/fields"
          }
        },
        "item_assets": {
          "type": "object",
          "additionalProperties": {
            "$ref": "#/definitions/fields"
          }
        },
        "summaries": {
          "$comment": "The values of summaries are not validated yet!"
        },
        "assets": {
          "type": "object",
          "additionalProperties": {
            "$ref": "#/definitions/fields"
          }
        }
      },
      "anyOf": [
        {
          "$comment": "Requires at least one provider to contain processing fields.",
          "type": "object",
          "required": [
            "providers"
          ],
          "properties": {
            "providers": {
              "type": "array",
              "contains": {
                "type": "object",
                "allOf": [
                  {
                    "type": "object",
                    "required": [
                      "roles"
                    ],
                    "properties": {
                      "roles": {
                        "type": "array",
                        "contains": {
                          "enum": [
                            "producer",
                            "processor"
                          ]
                        }
                      }
                    }
                  },
                  {
                    "$ref": "#/definitions/require_any_field"
                  }
                ]
              }
            }
          }
        },
        {
          "$comment": "Requires at least one asset to contain processing fields.",
          "type": "object",
          "required": [
            "assets"
          ],
          "properties": {
            "assets": {
              "type": "object",
              "not": {
                "additionalProperties": {
                  "not": {
                    "$ref": "#/definitions/require_any_field"
                  }
                }
              }
            }
          }
        },
        {
          "$comment": "Requires at least one item asset definition to contain processing fields.",
          "type": "object",
          "required": [
            "item_assets"
          ],
          "properties": {
            "item_assets": {
              "type": "object",
              "not": {
                "additionalProperties": {
                  "not": {
                    "$ref": "#/definitions/require_any_field"
                  }
                }
              }
            }
          }
        },
        {
          "type": "object",
          "$comment": "Requires at least one summary to be a processing field.",
          "required": [
            "summaries"
          ],
          "properties": {
            "summaries": {
              "$ref": "#/definitions/require_any_field"
            }
          }
        }
      ]
    }
  ],
  "definitions": {
    "stac_extensions": {
    },
    "require_provider_role": {
      "type": "object",
      "required": [
        "roles"
      ],
      "properties": {
        "roles": {
          "type": "array",
          "contains": {
            "enum": [
              "producer",
              "processor"
            ]
          }
        }
      }
    },
    "require_any_field": {
      "anyOf": [
        {"type": "object", "required": ["processing:expression"]},
        {"type": "object", "required": ["processing:lineage"]},
        {"type": "object", "required": ["processing:level"]},
        {"type": "object", "required": ["processing:facility"]},
        {"type": "object", "required": ["processing:software"]},
        {"type": "object", "required": ["processing:version"]},
        {"type": "object", "required": ["processing:datetime"]}
      ]
    },
    "fields": {
      "type": "object",
      "properties": {
        "processing:expression": {
          "title": "Processing Expression",
          "type": "object",
          "required": [
            "format",
            "expression"
          ],
          "properties": {
            "format": {
              "type": "string"
            },
            "expression": {
              "description": "Any data type, depending on the format chosen."
            }
          }
        },
        "processing:lineage": {
          "title": "Processing Lineage Information",
          "type": "string",
          "examples": [
            "Post Processing GRD"
          ]
        },
        "processing:level": {
          "title": "Processing Level",
          "type": "string",
          "examples": [
            "RAW",
            "L1",
            "L1A",
            "L1B",
            "L1C",
            "L2",
            "L2A",
            "L3",
            "L4"
          ]
        },
        "processing:facility": {
          "title": "Processing Facility",
          "type": "string",
          "examples": [
            "Copernicus S1 Core Ground Segment - DPA"
          ]
        },
        "processing:version": {
          "title": "Processing Version",
          "type": "string",
          "examples": [
            "0.2.0"
          ]
        },
        "processing:datetime": {
          "title": "Processing Datetime",
          "type": "string",
          "format": "date-time",
          "pattern": "(\\+00:00|Z)$",
          "examples": [
            "2020-01-05T12:34:55Z"
          ]
        },
        "processing:software": {
          "title": "Processing Software Name / version",
          "type": "object",
          "patternProperties": {
            ".{1,}": {
              "type": "string"
            }
          },
          "examples": [
            {
              "Sentinel-1 IPF": "002.71"
            }
          ]
        }
      },
      "patternProperties": {
        "^(?!processing:)": {}
      },
      "additionalProperties": false
    }
  }
}